1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to transmitting/receiving information in an Internet Protocol (IP) network, and more particularly, to allowing clients to transmit/receive information transmitted from a server.
2. Description of the Related Art
Internet Protocol Television (IPTV) is a service whereby an information service, a content service, or a broadcast service is provided to a television receiver by using the Internet. IPTV is a type of Internet Protocol (IP)-based service that is provided via the Internet infrastructure that has been built as demand for the Internet has increased.
FIG. 1 is a block diagram of a related art method of transmitting/receiving information in an IPTV network. Referring to FIG. 1, an IPTV server 10 has IPTV content and provides it to a first IPTV client 11 or a second IPTV client 12. The first or second IPTV client 11 or 12 is a device, such as an IPTV set top box, which requests that the IPTV server 10 provide a service and/or content or receives the service and/or content from the IPTV server 10.
Here, the IPTV server 10 transmits information regarding the service and/or content to IPTV clients via multicast, broadcast, or unicast. Information that must be transmitted to all IPTV clients is transmitted via multicast or broadcast, but information that must be transmitted to only a specific IPTV client is transmitted via unicast.
An IPTV client that has not received the information from the IPTV server 10 or that desires to receive the information from the IPTV server 10 via unicast, requests that the IPTV server 10 transmit the information and receives the information from the IPTV server 10 in response to the request.
In FIG. 1, each of the first and second IPTV clients 11 and 12 individually requests that the IPTV server 10 transmit information, and receives it from the IPTV server 10. Here, the information may include all information required for the first and second IPTV clients 11 and 12 to receive and use the service and/or content that the IPTV server 10 provides. For example, electronic program guide (EPG) information, electronic cinema guide (ECG) information, uniform resource locator (URL) information, and metadata information regarding the content that the IPTV server 10 holds, may be included in information exchanged among the IPTV server 10 and the IPTV clients 11 and 12. Information related to services provided by the IPTV server 10 (weather information, stock information, cultural information, etc.) may also be included in the information exchanged among the IPTV server 10 and the first and second IPTV clients 11 and 12.
When information is transmitted and received as illustrated in FIG. 1, the IPTV server 10 must make individual responses to requests from IPTV clients. Accordingly, when a large number of IPTV clients request the information at the same time, it may cause the IPTV server 10 to overload.
Also, when the first IPTV client 11 and the second IPTV client 12 are connected to the same router, thus forming a subnet, the above-described method is inefficient since the first IPTV client 11 and the second IPTV client 12 have to receive information from the IPTV server 10 although the first IPTV client 11 is adjacent to the second IPTV client 12 physically and temporally.